The invention relates to cap closures for pharmaceutical containers, especially for bottles containing substances intended for infusion, transfusion or injection, in which, for sealing, there is on the container neck a pierceable stopper-shaped or disk-shaped sealing element which is covered by a closing cap. A process for producing the sealing element used is also indicated.
Cap closures for pharmacuetical containers, using metal flanged caps or welded plastic caps, are known, for example, from German Offenlegungsschrift No. 2,727,737 and from German Patent Specification No. 2,327,553. In these, the bottle neck is sealed off by means of a pierceable disk-shaped or stopper-shaped elastic sealing element which is covered by a closing cap which is completely detachable or is detachable at the central region. In the case of metal flanged caps, this closing cap is fastened to the bottle neck by means of flanging on edge bead and, in the case of plastic caps, the cap is fastened to the neck of the plastic bottle as a result of welding by means of a flanged edge.
The stopper-shaped or disk-shaped sealing elements used for preclosing the bottle are solid and made of rubber or of a plastic with appropriate elastomeric properties. This solid design means a considerable waste of the relatively costly elastomeric rubber material. Moreover, there is a danger that during the storage period rubber constituents, especially plasticizer substances, will penetrate into the container contents, mix therewith and in so doing contaminate it. Moreover, during stamping of the solid rubber stoppers, stamping fragments which adhere firmly are obtained, and these can easily be introduced into the container. Furthermore, when the rubber stopper is perforated by means of a transfusion or injection needle, particles detached by the needle point can be introduced into the container contents and may be carried out together with the container contents.